When displaying information or other things on a sign, some type of illumination or reflection is typically used in order to increase the visibility of the sign, particularly when visibility is reduced in the environment by darkness, fog or precipitation. One example of this is road signs having their front side covered with a light reflecting surface that increases the visibility of the road sign as it is illuminated by, e.g., a headlight. Some associated drawbacks are that a properly working headlight must be directed towards the sign, and that all normal existing road signs provide approximately the same degree of reflection, even though some signs may be more important to observe than others.
Signs may further be provided with one or more separate lamps illuminating the front of the sign at an angle from the side without obstructing the sign. Signs also exist having installed lamps illuminating the sign from within inside a light admitting shell made of plastics or glass. Such external or internal separate lamps are typically fed with electric current from a power supply network, and are relatively costly to install and maintain. Further, this type of sign illumination is fairly vulnerable to external damage.
A great need may exist for increasing the attention to certain signs. In the case of road signs, it is unfortunately common that road-users look at a sign in a routine fashion without observing its significance, which in the worst case may result in an accident. In particular, in areas where a relatively great number of subsequent signs frequently occur, the risk increases for signs more important than others with respect to road safety being overlooked. Road-users should be able in good time to catch sight of certain important road signs, e.g. at speed limits, pedestrian crossings, schools and at crossings where drivers must give way to traffic or must stop.
DE 29701729 U1 discloses a road sign provided with light emitting diodes integrated in the sign in a fixed pattern which are provided with electric current from a solar collector. Some drawbacks with this solution are that the sign must initially be built with the light emitting diodes installed, and that a relatively significant operation is required to repair or modify the illumination pattern afterwards.
In general, there is a great need for a relatively inexpensive and sturdy solution for providing existing signs with illumination of optional strength and pattern in a simple and flexible manner, e.g. in order to increase the attention therefor.